Table 1.

Dissociation constants (apparent K_d) obtained from tryptophan fluorescence substrate-binding experiments with l-carnitine in the absence and presence of 50 mM NaCl

Protein	Apparent Kd, mM
	−Na+	+Na+
PmCaiT wild-type	3.63 ± 0.4	3.79 ± 0.35
PmCaiT R262E	38.75 ± 4.7	15.9 ± 1.3
PmCaiT R262A	39.6 ± 4.2	16.8 ± 1.2